The cells making up such living organisms as bacteria, plants,
animals and human beings can be looked upon as chemical miracles.
Simultaneously occurring in each and every one of these units of
life, invisible to the naked eye, are thousands of different
chemical reactions, necessary to the maintenance of biological
processes. Among the large number of components responsible for
cell functions, two groups of molecules are outstandingly
important. They are the nucleic acids - carriers of genetic
information - and the proteins, which catalyze the metabolism of
cells through their ability to act as enzymes.

Genetic information is programmed like a
chemical code in deoxyribonucleic acid, better known by its
abbreviated name of DNA. The cell, however, cannot decipher the
genetic code of the DNA molecule directly. Only when the code has
been transferred, with the aid of enzymes, to another type of
nucleic acid, ribonucleic acid or RNA, can it be interpreted by
the cell and used as a template for producing protein. Genetic
information, in other words, flows from the genetic code of DNA
to RNA and finally to the proteins, which in turn build up cells
and organisms having various functions. This is the molecular
reason for a frog looking different from a chaffinch and a hare
being able to run faster than a hedgehog.

Life would be impossible without enzymes,
the task of which is to catalyze the diversity of chemical
reactions which take place in biological cells. What is a
catalyst and what makes catalysis such a pivotal concept in
chemistry? The actual concept is not new. It was minted as early
as 1835 by the famous Swedish scientist Jöns Jacob
Berzelius, who described a catalyst as a molecule capable of
putting life into dormant chemical reactions. Berzelius had
observed that chemical processes, in addition to the reagents,
often needed an auxiliary substance - a catalyst - to occur. Let
us consider ordinary water, which consists of oxygen and
hydrogen. These two substances do not react very easily with one
another. Instead, small quantities of the metal platinum are
needed to accelerate or catalyze the formation of water. Today,
perhaps, the term catalyst is most often heard in connection with
purification of vehicle exhausts, a process in which the metals
platinum and rhodium catalyze the degradation of the contaminant
nitrous oxides.

As I said earlier, living cells also
require catalysis. A certain enzyme, for example, is needed to
catalyze the breakdown of starch into glucose and then other
enzymes are needed to burn the glucose and supply the cell with
necessary energy. In green plants, enzymes are needed which can
convert atmospheric carbon dioxide into complicated carbon
compounds such as starch and cellulose.

As recently as the early 1980s, the
generally accepted view among scientists was that enzymes were
proteins. The idea of proteins having a monopole of biocatalytic
capacity has been deeply rooted, and created a fundamental dogma
of biochemistry. This is the very basic perspective in which we
have to regard the discovery today being rewarded with the Nobel
Prize for Chemistry. When Sidney Altman showed that the enzyme
denoted RNaseP only needed RNA in order to function, and when
Thomas Cech discovered self-catalytic splicing of a nucleic acid
fragment from an immature RNA molecule, this dogma was well and
truly holed below the waterline. They had shown that RNA can have
catalytic capacity and can function as an enzyme. The discovery
of catalytic RNA came as a great surprise and was indeed met with
a certain amount of scepticism. Who could ever have suspected
that scientists, as recently as in our own decade, were missing
such a fundamental component in their understanding of the
molecular prerequisites of life? Altman's and Cech's discoveries
not only mean that the introductory chapters of our chemistry and
biology textbooks will have to be rewritten, they also herald a
new way of thinking and are a call to new biochemical
research.

The discovery of catalytic properties in
RNA also gives us a new insight into the way in which biological
processes once began on this earth, billions of years ago.
Researchers have wondered which were the first biological
molecules. How could life begin if the DNA molecules of the
genetic code can only be reproduced and deciphered with the aid
of protein enzymes, and proteins can only be produced by means of
genetic information from DNA? Which came first, the chicken or
the egg? Altman and Cech have now found the missing link.
Probably it was the RNA molecule that came first. This molecule
has the properties needed by an original biomolecule, because it
is capable of being both genetic code and enzyme at one and the
same time.

Professor Altman, Professor Cech, you have
made the unexpected discovery that RNA is not only a molecule of
heredity in living cells, but also can serve as a biocatalyst.
This finding, which went against the most basic dogma in
biochemistry, was initially met with scepticism by the scientific
community. However, your personal determination and experimental
skills have overcome all resistance, and today your discovery of
catalytic RNA opens up new and exciting possibilities for future
basic and applied chemical research.

In recognition of your important
contributions to chemistry, the Royal Swedish Academy of Sciences
has decided to confer upon you this year's Nobel Prize for
Chemistry. It is a privilege and pleasure for me to convey to you
the warmest congratulations of the Academy and to ask you to
receive your prizes from the hands of His Majesty the King.